Andršová Irena, Hnatkova Katerina, Šišáková Martina, Toman Ondřej, Smetana Peter, Huster Katharina M, Barthel Petra, Novotný Tomáš, Schmidt Georg, Malik Marek
Faculty of Medicine, Department of Internal Medicine and Cardiology, University Hospital Brno, Masaryk University, Brno, Czechia.
National Heart and Lung Institute, Imperial College, London, United Kingdom.
Front Physiol. 2022 Feb 7;12:814542. doi: 10.3389/fphys.2021.814542. eCollection 2021.
While it is now well-understood that the extent of QT interval changes due to underlying heart rate differences (i.e., the QT/RR adaptation) needs to be distinguished from the speed with which the QT interval reacts to heart rate changes (i.e., the so-called QT/RR hysteresis), gaps still exist in the physiologic understanding of QT/RR hysteresis processes. This study was designed to address the questions of whether the speed of QT adaptation to heart rate changes is driven by time or by number of cardiac cycles; whether QT interval adaptation speed is the same when heart rate accelerates and decelerates; and whether the characteristics of QT/RR hysteresis are related to age and sex. The study evaluated 897,570 measurements of QT intervals together with their 5-min histories of preceding RR intervals, all recorded in 751 healthy volunteers (336 females) aged 34.3 ± 9.5 years. Three different QT/RR adaptation models were combined with exponential decay models that distinguished time-based and interval-based QT/RR hysteresis. In each subject and for each modelling combination, a best-fit combination of modelling parameters was obtained by seeking minimal regression residuals. The results showed that the response of QT/RR hysteresis appears to be driven by absolute time rather than by the number of cardiac cycles. The speed of QT/RR hysteresis was found decreasing with increasing age whilst the duration of individually rate corrected QTc interval was found increasing with increasing age. Contrary to the longer QTc intervals, QT/RR hysteresis speed was faster in females. QT/RR hysteresis differences between heart rate acceleration and deceleration were not found to be physiologically systematic (i.e., they differed among different healthy subjects), but on average, QT/RR hysteresis speed was found slower after heart rate acceleration than after rate deceleration.
虽然现在已经清楚地认识到，由于潜在心率差异导致的QT间期变化程度（即QT/RR适应性）需要与QT间期对心率变化的反应速度（即所谓的QT/RR滞后）区分开来，但在对QT/RR滞后过程的生理理解方面仍然存在差距。本研究旨在解决以下问题：QT间期对心率变化的适应速度是由时间还是由心动周期数驱动；心率加速和减速时QT间期适应速度是否相同；以及QT/RR滞后的特征是否与年龄和性别有关。该研究评估了751名年龄在34.3±9.5岁的健康志愿者（336名女性）记录的897,570次QT间期测量值及其前5分钟的RR间期历史。将三种不同的QT/RR适应模型与区分基于时间和基于间期的QT/RR滞后的指数衰减模型相结合。在每个受试者和每种建模组合中，通过寻求最小回归残差获得建模参数的最佳拟合组合。结果表明，QT/RR滞后的反应似乎是由绝对时间而非心动周期数驱动的。发现QT/RR滞后速度随着年龄的增加而降低，而个体心率校正后的QTc间期持续时间随着年龄的增加而增加。与较长的QTc间期相反，女性的QT/RR滞后速度更快。未发现心率加速和减速之间的QT/RR滞后差异具有生理系统性（即不同健康受试者之间存在差异），但平均而言，心率加速后的QT/RR滞后速度比心率减速后慢。
